Ionic Liquid Catalyzed Alkylation Processes & Systems

CATEGORY: IONIC LIQUIDS
PATENT
Ionic Liquid Catalyzed Alkylation Processes & Systems
Pub. No.:    WO/2013/039581    International Application No.:    PCT/US2012/042298
Publication Date:  21.03.2013 International Filing Date:  13.06.2012
Applicants:  CHEVRON U.S.A. INC. [US/US]; 6001 Bollinger Canyon Road San Ramon, CA 94583 (US) (For All Designated States Except US).
Inventors: 
LUO, Huping; (US).
AHMED, Moinuddin; (US) 
Abstract:  
Ionic liquid alkylation processes may comprise contacting at least one hydrocarbon stream with an ionic liquid catalyst in an ionic liquid alkylation zone under ionic liquid alkylation conditions, cooling at least one of a reactor effluent and a hydrocarbon phase of the reactor effluent, and recycling the cooled reactor effluent or cooled hydrocarbon phase to the ionic liquid alkylation zone. Ionic liquid alkylation systems for performing ionic liquid catalyzed alkylation processes are also disclosed.
TECHNICAL FIELD
The present invention relates to ionic liquid catalyzed alkylation processes and systems.
BACKGROUND
Hydrofluoric acid (HF) is used as a catalyst in conventional industrial processes to perform reactions such as aromatic and olefin alkylation, including refinery processes for the production of high-octane gasoline, distillate, and lubricating base oil. The hazards of HF, e.g., related to HF volatility, are well documented. The use of additives to reduce HF volatility is expensive and does not eliminate the need for large quantities of HF in the plant.
Efforts to develop safer, alternative catalysts have encountered serious challenges. The conversion of HF alkylation units to use sulfuric acid (H2S04) as catalyst requires significant added capital and operating expense, and at the same time introduces the hazards associated with highly corrosive concentrated H2S04. Further, solid alkylation catalysts have proved difficult to commercialize due to rapid fouling and deactivation.
Figure 1 schematically represents an HF alkylation unit 10, according to the prior art. HF alkylation unit 10 includes a hydrocarbon feed line 12, an HF reactor 16, and an HF settler 18 coupled to HF reactor 16 for separating an HF/hydrocarbon mixture into a hydrocarbon phase 20 and an HF phase 22. In conventional HF alkylation processes, a large excess of HF catalyst is used such that the HF forms the continuous liquid phase in which the hydrocarbon feeds are dispersed. Due to the relatively large volume of HF catalyst used in HF alkylation, reaction heat may be adequately dissipated by recycling the HF phase via heat exchanger 24. In Figure 1, heat exchanger 24 is shown as being
external to HF reactor 16. In other designs, the heat exchanger could be located inside the reactor to remove the reaction heat from both the hydrocarbon and the HF together.
The quest for alternative catalytic systems to replace conventional HF and H2SO4 catalysts in alkylation processes has been researched by various groups in both academic and industrial institutions. Thus far, no alternative catalyst for performing such processes has been commercialized.
Recently there has been considerable interest in metal halide ionic liquid catalysts as alternatives to HF and H2SO4 catalysts. As an example, the ionic liquid catalyzed alkylation of isoparaffins with olefins is disclosed in U.S. Patent No. 7,432,408 to Timken, et al. Further, U.S. Patent No. 7,572,943 to Elomari, et al. discloses the ionic liquid catalyzed oligomerization of olefins and the alkylation of the resulting
oligomers(s) with isoparaffins to produce alkylated olefin oligomers.
There is a need for ionic liquid catalyzed alkylation processes and for ionic liquid alkylation systems for conducting such processes.
SUMMARY
In an embodiment of the present invention there is provided an ionic liquid catalyzed alkylation process, comprising contacting at least one hydrocarbon stream with an ionic liquid catalyst in an ionic liquid alkylation zone under ionic liquid alkylation conditions, separating a reactor effluent from the ionic liquid alkylation zone into an ionic liquid phase and a hydrocarbon phase, cooling a first portion of the hydrocarbon phase to provide a cooled hydrocarbon phase, and recycling the cooled hydrocarbon phase to the ionic liquid alkylation zone.
In another embodiment there is provided an ionic liquid catalyzed alkylation process comprising contacting at least one hydrocarbon stream with an ionic liquid catalyst in an ionic liquid alkylation zone under ionic liquid alkylation conditions, cooling a first portion of a reactor effluent from the ionic liquid alkylation zone to provide a cooled reactor effluent, and recycling the cooled reactor effluent to the ionic liquid alkylation zone.
In another embodiment there is provided an ionic liquid alkylation system comprising an ionic liquid alkylation reactor; an ionic liquid/hydrocarbon injection unit, in fluid communication with the ionic liquid alkylation reactor, for injecting an ionic
liquid/hydrocarbon mixture into the ionic liquid alkylation reactor; an ionic
liquid/hydrocarbon separation unit, in fluid communication with the ionic liquid alkylation reactor, for receiving a reactor effluent from the ionic liquid alkylation reactor and for separating the reactor effluent into an ionic liquid phase and a hydrocarbon phase; and a heat exchanger, in fluid communication with the ionic liquid/hydrocarbon separation unit, for cooling at least a portion of the hydrocarbon phase to provide a cooled hydrocarbon phase, wherein the heat exchanger is in fluid communication with the ionic liquid/hydrocarbon injection unit for feeding the cooled hydrocarbon phase to the ionic liquid alkylation reactor.
In another embodiment there is provided an ionic liquid alkylation system comprising an ionic liquid alkylation reactor; an ionic liquid/hydrocarbon injection unit, in fluid communication with the ionic liquid alkylation reactor, for injecting an ionic
liquid/hydrocarbon mixture into the ionic liquid alkylation reactor; a heat exchanger, in fluid communication with the ionic liquid alkylation reactor, for cooling a first portion of a reactor effluent from the ionic liquid alkylation reactor to provide a cooled reactor effluent; and an ionic liquid/hydrocarbon separation unit, in fluid communication with the ionic liquid alkylation reactor, for receiving a second portion of the reactor effluent from the ionic liquid alkylation reactor and for separating the second portion of the reactor effluent into a hydrocarbon phase and an ionic liquid phase.
As used herein, the terms "comprising" and "comprises" mean the inclusion of named elements or steps that are identified following those terms, but not necessarily excluding other unnamed elements or steps.
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